Thursday, September 4, 2008

Fall Warbler Identification: Part 5

The most common identification problem with this group of warblers occurs when a birder sees an eye-ring and assumes the identity of it without really seeing the bird well. The Canada is by far the least common of these four warblers but they do occur very regularly in their range.

Nashville: This warbler has a gray hood, yellow breast, and white eye-ring. It has much more yellow than the Magnolia and it never shows any streaking on the sides as the Magnolia does. The Nashville always has more yellow on the breast than the Chestnut-sided, as the Chestnut-sided does not show any yellow on the breast. The biggest challenge comes between the Nashville and Canada. The main difference between the two is the back color. The Canada has a completely slate gray back and the Nashville has a gray to greenish back. The Nashville is a much more active warbler, and the Canada acts more like a flycatcher.

Chestnut-sided: This warbler should not really ever be confused with the other three in this grouping because it does not have any yellow on the chest or belly. Some people may confuse these because of the white-eye ring but always look for the yellow. The Chestnut-sided has a pale gray chest and a very distinctive yellow-green color on the upperparts. Also look for the yellow wing-bars on this warbler.

Magnolia: The only time that this warbler might be confused with others is when it is a first fall female. Look for a pale gray neckband, lots of yellow in the belly and breast, gray head, and white wing-bars. The Nashville will always show a strong eye-ring, if the Magnolia shows an eye-ring at all, it will be a very weak eye-ring. It also differs from the Canada by having wing bars and striping on the back, the Canada will always show a plain gray back.

Canada: The Canada has a much different behavior than the other three warblers in this group and all the warblers in the United States. It perches upright like a flycatcher and is much more stationary than the other warblers. The best field mark for the Canada is the black necklace, each Canada shows this necklace but it is very faded on first year birds, especially the first fall females. Another good field mark to use with Canada is the big white eye-ring combined with the plain gray back. The Nashville has a plain back but it is much greener than the back of the Canada.

The more you work on seeing the whole bird in its environment instead of just seeing field marks the better you will become at identifying all birds. If you have any questions about how to identify any of the warblers discussed so far, let me know with a comment or email.